KR20050102323A - Coating thickness detector system and method of thin film forming process - Google Patents

Abstract

In the process of forming a precision coating film or a fine thin film on the surface of the workpiece in the thin film forming process, the thickness of the coating film on the working surface is continuously measured by a non-contact method, and feedback control is performed according to the measured result to obtain a uniform coating film. To make the thickness molded,

A workpiece, a means for transferring the workpiece at a constant speed, a coating liquid discharge device disposed on the outer center line of the transfer means to form a coating film on the surface of the workpiece to be transported, and an upper surface of the workpiece to which the coating film is molded and transported And a coating thickness detector configured to be disposed at and fixed to irradiate white light having a wide wavelength distribution on the surface of the workpiece, and to reflect the reflected light from the coated film of the workpiece by detecting and analyzing reflected light.

In addition, the process of causing the coating film to focus on the surface of the workpiece to be formed at a different depth depending on the wavelength, collecting light reflected from the surface of the workpiece, analyzing the wavelength, and analyzing the light being analyzed by line tracking and vector analysis. Extracting the thickness of the coating film by applying a technique; and controlling feedback of the discharge amount of the coating liquid for forming the coating film according to the extracted coating film thickness.

Therefore, by forming a coating film on the surface of the workpiece to detect the thickness of the coated film in real time and feedback control the interlocking device, thereby providing the reliability of the product by forming a uniform coating film thickness, thereby eliminating defects To provide stability of the process.

In addition, there is an effect that can diagnose the state of the peripheral device to be interlocked from the detection data of the coating film thickness on the workpiece.

Description

Coating Thickness Detector System and Method of Thin Film Forming Process

The present invention relates to an apparatus for detecting the thickness of a coating film in a thin film forming process, and more particularly, in the process of forming a fine coating film or a fine thin film on the surface of a work object, the thickness of the coating film on the working surface is continuously controlled by a non-contact method. The present invention relates to a coating thickness detecting apparatus and a method in a thin film forming process for measuring a thickness of a film, and performing feedback control according to the measured result to form a uniform coating film thickness.

In general, in the thin film forming process, a fine phosphor coating film is attached to a surface of a glass (LCD) of a flat panel display panel, which is a work object, or a glass of a plasma display panel having a lattice arrangement, or a fine surface is formed on a surface of a thin film electrode using a coating liquid discharge device. Precise coating of graphite film.

Maintaining the uniformity of the coating film is a very important factor that affects the quality of the product, or the coating liquid is discharged in a uniform amount due to pressure variation in the nozzle of the coating liquid discharge device or aging of the nozzle itself. As a result, the thickness of the coating film is deviated, leading to deterioration of the quality of the workpiece. In severe cases, expensive glass and electrodes are treated as defective and destroyed, or many problems occur in the process of having to go through the cleaning process again. .

Therefore, in order to maintain a uniform coating film thickness in the process of forming a coating film on the workpiece as described above, a method of measuring the thickness and distance of the coated micro surface by applying an inductive detection sensor is applied. Since the error of the thickness is about 1 to 2 μm, the microscopic measurement is not possible, so it is impossible to precisely measure the thickness.

In addition, the above-described inductive detection sensor is possible only when the workpiece is a metal, the problem occurs that can not be applied when the medium is a non-metal.

In addition, a method of measuring a coated thickness by applying a capacitive sensor and an ultrasonic sensor as another method has been applied, but the measurement degree is so large that there are many problems to apply to fine measurement.

In particular, in the case of performing a coating operation on the opaque film, a problem more difficult to measure the thickness of the coated working surface occurs.

The present invention has been proposed to solve the above problems, and its object is to focus on different depths depending on the wavelength of the base line and the coated surface of the workpiece surface in the process of attaching a fine coating film or a fine thin film to the surface of the workpiece. By irradiating light to form a light, by analyzing the wavelength of the reflected light reflected from the surface of the workpiece, the coating thickness on the working surface is continuously measured by a non-contact method, and the feedback control according to the measured result is executed to perform a uniform coating. The thickness of the membrane is to be molded.

In addition, another object of the present invention is to be able to utilize as data and measurement data for maintenance through the detection of the thickness of the fine coating film on the surface of the workpiece.

The present invention in order to achieve the above object in the thin film forming process, the workpiece; Means for transporting the work object at a constant speed; A coating liquid discharge device disposed on an outer center line of the transfer means to form a coating film on the surface of the workpiece to be transferred; The coating film is formed and fixed on the upper surface of the workpiece to be transported, and is irradiated with light in a form in which the surface of the workpiece is focused at a different depth depending on the wavelength, and the reflection from the coating film of the workpiece detects and analyzes reflected light. It characterized in that it comprises a coding thickness detector for detecting the thickness of the coating film.

In addition, when the coating film forming is started on the surface of the workpiece, the optical particle sensor generates a light irradiation; Irradiating each of the wavelengths of the irradiated light to focus at different depths; Analyzing each wavelength by collecting reflected light reflected from the surface of the workpiece; Extracting line components of both baselines of the workpiece from the analyzed wavelengths; Extracting inclination and intercept between the base lines on both sides and applying the same to smooth the inclined curve of the measured data to extract pure coating surface data; Extracting a normal vector by extracting and calculating a vector component for each cell region of the coating plane; Multiplying the extracted normal vector by a scalar amount of each pixel and extracting the extracted normal vector into 3D spatial coordinates through vector transformation in Cartesian coordinates; It provides a coating thickness detection method in a thin film forming process, comprising the step of extracting the curved surface having a different thickness of the coating film from the 3D spatial coordinates to detect the thickness variation of the coating film and then feedback control of the injection amount of the coating liquid. .

In addition, the step of irradiating light to the surface of the workpiece to be coated coating film; Analyzing wavelengths by collecting light reflected from the surface of the workpiece; Extracting the thickness of the coating film from the wavelength-analyzed light by applying a line tracking technique and a vector analysis technique; According to the thickness of the extracted coating film provides a coating thickness detection method in a thin film forming process comprising the step of controlling the feedback of the discharge amount of the coating liquid for forming the coating film.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic perspective view for explaining an embodiment according to the present invention, which is a schematic configuration diagram of a system for detecting a coating thickness of an electrode material in a system for coating a graphite film on a surface of a thin film electrode.

As can be seen in the drawings, an embodiment of the present invention is a thin film electrode (hereinafter referred to as an electrode), which is a work object, a roller R for transferring the electrode G, and an outer center of the roller R. The coating liquid discharge device 200 which is disposed in a line and coats an electrode material on the surface of the electrode G to be transferred, and is fixed to an upper surface of the electrode G to which the electrode material is coated and transported to be irradiated with light and the electrode. Reflection at the coating surface of (G) is composed of a coding thickness detection device 100 for analyzing the reflected light.

The coating thickness detecting apparatus 100 may detect a plurality of optical particle sensors 103 in the width direction of the electrode G, which is the workpiece, in order to detect a thickness of the coating film minutely coated on the surface of the electrode G, which is the workpiece. ) Are arranged at regular intervals and installed in a line shape having a right angle or a constant inclination angle with respect to the conveying direction.

Therefore, the coating thickness detecting apparatus 100 having a line shape irradiates the base line and the coated surface of the surface of the work object so as to focus at different depths according to the wavelength of the light source, and the reflected light reflected from each surface of the work object. The thickness of the coating film on the working surface was continuously measured by a non-contact method by performing the analysis, and the feedback control according to the measured result was executed so that the uniform coating film thickness could be formed, and the data on the thickness of the coating film detected. To be used as data for maintenance of the coating liquid discharge device, and to be used as reference data in various operations related thereto.

The structure of the optical particle sensor 103 constituting the coating film thickness detecting apparatus 100 will be described in more detail with reference to FIG. 2.

The optical particle sensor 103 focuses the light irradiating means 120 for generating light, preferably white light, and irradiates the light irradiated from the light irradiating means 120 to form an object G. The light converging means 140 for focusing at different depths depending on the wavelength near the surface, the beam splitter 160 for changing the direction of the reflected light reflected from the surface of the electrode G, and the beam splitter 160 It may be provided with a detection means 180 for detecting the wavelength of the reflected light detected in accordance with the change of direction.

The detection unit 180 senses the intensity of the reflected light reflected from the surface of the electrode G according to the sensitivity for each wavelength of each of the first and second imaging devices 191 and 193, and analyzes the sensed sensitivity. And it has a structure that can be transmitted to the controller (C) for measuring the thickness of the coating film by calculation through a set algorithm.

The light irradiating means 120 includes a light source LS for generating white light, a lens assembly 121 for condensing light generated by the light source LS, and light passing through the light focused in the lens assembly 121. Passing member 123, and the first filter 125 for adjusting the sensitivity for each wavelength of the light passing through the light passing member 123.

The light source LS may emit white light, and a conventional one may be used.

The light passing member 123 has a slit 123a having a predetermined length, is disposed at a focal position of the lens assembly 121, and a position through which the light of the light source LS can pass through the slit 123a. It is preferably arranged in.

In particular, the slit 123a provided in the light passing member 123 is preferably formed of an elongated long hole so as to have a vertical or constant inclination with respect to the surface in the traveling direction of the electrode G, which is a work object.

The first filter 125 serves to filter the wavelength distribution (spectrum) of the light irradiated onto the surface of the electrode G, which is the workpiece, to be adjusted and passed.

The light converging means 140 is composed of a lens assembly that allows the focal length to be varied according to the wavelength of light due to chromatic aberration, and the focus is on the base line A and the surface of the electrode G as the work object. To form near the depth of the coating film (B).

The light focusing unit 140 may be a zone plate or a panel lens.

On the other hand, the beam splitter 160 is disposed between the light irradiation means 120 and the light focusing means 140 to pass the light of the light source LS, and passes through the light focusing means 140 to the electrode Detecting the reflected light reflected from the surface of the base line (A) and the coating film (B) of the electrode (G) to focus near the depth of the base line (A) and the coating film (B) of (G) ( 180) serves to change the direction to be irradiated to the side.

The detecting means 180 is another light passing member 181 having a slit through which the light irradiated by the beam splitter 160 can pass therethrough, and the light passing through the light passing member 181. Another lens assembly 183 for focusing, another beam splitter 185 for passing according to the wavelength of light passing through the lens assembly 183 or reflecting at a predetermined angle to separate in two directions, the beam splitter 185 2nd, 3rd filters 187 and 189 for filtering the band acting as noise in the light passed by), and 1st and 2nd for detecting the light passing through the second and third filters 187 and 189. Image pickup devices 191 and 193 may be included.

The controller C calculates the sensitivity of the light detected by the first and second imaging devices 191 and 193 in the electrode G, which is a work object, by using a set algorithm, and coats the surface of the electrode G by analyzing the calculated result. The film thickness is continuously detected, and the coating liquid discharge device 200 is feedback-controlled according to the detected result so that a uniform coating film is formed on the surface of the electrode G.

In addition, the controller C is provided with display means to display information on the uniformity of the coating film on the surface of the electrode G.

The controller C includes an A / D conversion means, and differentially or differentially calculates two sensitivity detected by the first and second imaging elements 191 and 193 in the detection means 180 using a differential amplifier. Extracted by the dimensional function, the extracted function value is converted into a digital signal through the A / D conversion means, and the thickness of the real-time coating film is detected by analyzing the histogram.

The operation of detecting the coating film thickness of the surface of the electrode G through the coating thickness detecting apparatus 100 applicable to the present invention made as described above will be described in detail with reference to FIGS. 3 and 4 as follows.

When the process of coating the electrode material on the electrode (G) which is the work object is started, the coating liquid discharge device 200 forms a coating film on the surface of the electrode (G) which is transferred in the direction of the arrow by the roller (S101). .

At this time, the light source LS in the light irradiation means 120 of the plurality of optical particle sensors 103 constituting the coating film thickness detecting apparatus 100 according to the present invention generates white light to generate the base of the electrode G. It irradiates on the line A and the coating film B of a surface (S102).

The white light generated by the light source LS is focused by the lens assembly 121 and passes through the slit 123a of the light passing member 123 and then passes through the first filter 124.

In this case, the first filter 125 filters the white light of the light source LS into light having different sensitivity and irradiates the light focusing unit 140.

The light focusing means 140 focuses light at different depths according to wavelengths on the base line A of the electrode G and the coating film B on the surface of the light adjusted to different sensitivity by chromatic aberration using the lens assembly. This bears.

Since the light irradiated on the base line A of the electrode G and the coating film B on the surface as described above is reflected from the surface of the base line A and the coating film B, the reflected light is beam splitter The direction of travel is switched by the 160 and is irradiated to the detection means 180 side.

At this time, the light passing member 181 in the detecting means 180 passes through the light irradiated by the beam splitter 160 and is focused through the lens assembly 183 and then through the beam splitter 185. The detected light is separated by passing through the wavelength of the reflected light or reflecting at a predetermined angle.

As described above, each light separated by the beam splitter 185 in the detection unit 180 is extracted by only the wavelength of the band required by the second and third filters 187 and 189 to be applied to the first and second image pickup devices 191 and 193. It is input and sent to the controller C.

In the light irradiation means 120, the controller C detects a light having a wavelength at which the focal point is accurately focused among light of various wavelengths irradiated on the surface of the base line A and the coating film B of the electrode G. The intensity of the reflected light becomes the strongest value, and the intensity of the reflected light detected by the controller C is low in the case of the light of the wavelength when the irradiated light does not focus accurately at the fixed position according to the variation in the thickness of the coating film. It becomes

Therefore, the intensity of the reflected light detected by the controller C is detected as light of uniform intensity with sensitivity to different wavelengths through the beam splitter 185 (S103).

Therefore, the controller C performs wavelength analysis for detecting the coating film thickness from the reflected light detected with different sensitivity as described above (S104).

At this time, the value detected at both baselines of the electrode G becomes the surface position of the electrode G, and the value above the surface position is the thickness of the coating film.

However, the electrode G, which is conveyed in the direction of the arrow by the roller R, is likely to deform without having a constant value on both sides of the base line A due to various conditions, and thus the surface position of the electrode G. In-baseline reference setting is required.

Accordingly, the controller C measures the inflection point of the region corresponding to the base line A by analyzing the wavelength of the detected reflected light, and extracts the line component of the base line A (S105). The linear fitting process is performed on the data of the line component to an appropriate value through the application of), and the slope and intercept between the base lines A on both sides are calculated (S106).

Smoothing and subtracting the inclined curve of the entire measurement data using the slope and intercept between the two base lines (A) calculated above to calculate only the data of the pure coating surface (S107).

In addition, by taking a sample grid (Simple Cubic) for the area of each cell (Cell) forming a plane on the calculated coating surface, and performing the region processing by Prewitt which is one of the image processing method of eight vector components, Each unit vector is calculated and a normal vector for a plane vector is calculated by configuring a combination component of a plane for each unit vector (S108) (S109).

In this way, the 360 degree direction is divided into 90 degree regions through the prewitt region processing using the vector converted function, and then a normal vector of each pixel is calculated within the divided angles.

The normal vector of each pixel calculated as described above is multiplied by a scalar amount, converted to a vector in Cartesian coordinates, and then converted to a 3D spatial coordinate (S110).

That is, three-dimensional shape data for a collection of planar grids is calculated using the calculated vector components, coordinates, and values for the analyzed depth information.

Subsequently, the coating liquid discharge device 200 is discharged by calculating three-dimensional data of the planar lattice meeting by smoothing and vector analysis of the base line A of the electrode G to which the line tracking technique is applied as described above. Extraction of the curvature for the variation of the coating film thickness on the surface of the electrode G generated due to the pressure imbalance and other causes (S111) indicates the corresponding information through the display means (S112).

At the same time, by controlling the pressure and the amount of the coating liquid derived from the nozzle of the coating liquid discharge device 200, a uniform coating film thickness is molded (S113).

In addition, through the detection of the coating film thickness as described above, it is possible to estimate the degree of aging of the nozzle to estimate the replacement time of the nozzle and general information about the coating liquid discharge device 200.

As shown in FIG. 3, the signal for the reflected light detected by the detection means 180 from the surface of the base line A and the coating film B of the electrode G through the above-described process is output to the amplifier 300. When the power is amplified to a predetermined level and applied to the controller (C), the controller (C) extracts the thickness of the coating film on the surface of the electrode (G) through the analysis of the above process.

Subsequently, the pumping amount of the pump 220 is controlled by controlling the driving of the motor 210 of the coating liquid deriving apparatus 200 based on the extracted data, from the tank 240 in which the coating liquid is stored. By adjusting the flow rate or pressure, and controlling the valve 230 to adjust the amount of the coating liquid supplied to the nozzle 250, a uniform coating film thickness can be formed on the surface of the electrode G at all times.

In the above example, the feedback is measured by measuring the thickness of the coating film formed on the surface of the electrode G. For example, as shown in FIG. 5, the coating in the process of applying the phosphor film to the lattice arrangement of the flat panel display panel or the PDP panel is performed. It is also used in the measurement of the film thickness, which can be easily carried out by those skilled in the art as in the above-described embodiment, a detailed description thereof will be omitted.

As described above, the present invention detects the thickness of the coated film in real time in the process of forming the coating film on the surface of the workpiece in the thin film forming process and feedback control the interlocking device, thereby providing the reliability of the product by forming a uniform coating film thickness. Thereby eliminating the occurrence of defects to provide stability of the process.

In addition, there is an effect that can diagnose the state of the peripheral device to be interlocked from the detection data of the coating film thickness on the workpiece.

1 is a perspective view schematically showing a coating thickness detection apparatus in a thin film forming process for explaining an embodiment according to the present invention.

Figure 2 is a detailed configuration of the coating thickness detection apparatus in a thin film forming process according to an embodiment of the present invention.

Figure 3 is a schematic configuration diagram of a system that is controlled in conjunction with the coating thickness detection apparatus in a thin film forming process according to an embodiment of the present invention.

4 is a flowchart for performing coating thickness detection in a thin film forming process according to an embodiment of the present invention.

5 is a cross-sectional view showing another application example of the coating thickness detection apparatus in the thin film forming process according to an embodiment of the present invention.

Claims (17)

In the thin film forming process, Work object; Means for transporting the work object at a constant speed; A coating liquid discharge device disposed on an outer center line of the transfer means to form a coating film on the surface of the workpiece to be transferred; The coating film is formed and fixed on the upper surface of the workpiece to be transported, and irradiates light through the light focusing means to focus the light at different depths depending on the wavelength of light near the surface of the workpiece. The coating is a coating thickness detection device in a linear thin film process, characterized in that it comprises a coding thickness detection device for detecting and analyzing the reflected light to detect the thickness of the coating film. The method of claim 1, The coating thickness detecting device detects the thickness of the coating film coated on the workpiece by installing a plurality of optical particle sensors at regular intervals in the width direction of the workpiece and having a line shape having a right angle or a predetermined inclination angle with respect to the conveying direction. Coating thickness detection apparatus in the thin film forming process, characterized in that. The method of claim 1, The coating thickness detector has a wide and even distribution of light sources, irradiates the baseline and the coated surface of the workpiece surface to focus at different depths according to the wavelength, and reflects the reflected light reflected from the workpiece surface. The coating thickness detection device in the thin film forming process, characterized in that for detecting, by analyzing the wavelength and continuously measuring the thickness of the coating film on the working surface by a non-contact method, and feedback control the interlock according to the measured result. The method of claim 1, The optical particle sensor comprises a light irradiation means for generating light having a wide line width to separate and irradiate to focus at different depths according to the wavelength; Light focusing means for focusing the light irradiated from the light irradiating means to fix the focus at an adjusted position of each surface of the workpiece; A beam splitter disposed between the light irradiating means and the light converging means to change the direction of light reflected from the surface of the workpiece; And detecting means for receiving the intensity of light detected in accordance with the change of direction of the beam splitter. The method of claim 4, wherein The light irradiation means is a light source; A lens assembly for focusing the light generated by the light source and irradiated; A light passing member disposed at a focal position of the lens assembly to allow focused light to pass through a slit of a predetermined length; And a first filter for filtering the light having passed through the light passing member with light having a wide line width. The method of claim 4, wherein  The slit provided in the light passing member is a coating thickness detection device in the thin film forming process, characterized in that the elongated long hole to have a vertical or constant inclination with respect to the direction of the work. The method of claim 4, wherein The optical focusing device may be formed of a lens assembly in which a focal length may vary according to sensitivity due to chromatic aberration. The method of claim 4, wherein The light converging means focuses the base line of the workpiece with respect to light having one wavelength, and focuses the coated surface of the workpiece with light having a different wavelength. Coating thickness detector in the process. The method of claim 4, wherein The optical focusing device is a coating thickness detection device in a thin film forming process, characterized in that a zoom plate or a panel lens is used to generate chromatic aberration to vary the focal length. The method of claim 4, wherein The detection means includes a light passing member having a pin hole through which the light reflected by the direction is passed; A lens assembly focusing the light passing through the light passing member; A beam splitter configured to separate the light by passing the light passing through the lens assembly according to each wavelength or reflecting the light at a predetermined angle; Second and third filters passing only wavelengths of a band to be detected in the light passed by the beam splitter; And a first and second imaging device configured to sense light passing through the second and third filters. The method of claim 1, The coating thickness detecting apparatus displays the detection information on the coating film thickness coated on the surface of the workpiece, and the display means for displaying the coating film in 3D with respect to the plane of the coating film. . In the thin film forming process, When the coating film forming is started on the surface of the workpiece, the optical particle sensor generates and irradiates light; Irradiating different focal points of the irradiated light to focus on fixed surfaces of the workpiece; Analyzing sensitivity by collecting reflected light reflected from a surface of the workpiece; Extracting line components of both baselines of the workpiece from the analyzed sensitivity; Extracting inclination and intercept between the base lines on both sides and applying the same to smooth the inclined curve of the measured data to extract pure coating surface data; Extracting a normal vector by extracting and calculating a vector component for each cell region of the coating plane; Multiplying the extracted normal vector by a scalar amount of each pixel and extracting the extracted normal vector into 3D spatial coordinates through vector transformation in Cartesian coordinates; And detecting a thickness variation of the coating film by extracting curved surfaces having different thicknesses of the coating film from the 3D spatial coordinates, and then controlling feedback of the injection amount of the coating liquid. The method of claim 12, The coating thickness detection method in the thin film forming process, characterized in that to focus at different depths according to the wavelength using the chromatic aberration of the lens assembly. The method of claim 12, The pure coating surface data extraction on the surface of the workpiece is measured by measuring the inflection point of the base line region, which is the surface on which the coating film is formed, and extracting the line components to linearize the line components by applying a line tracking technique, A method of detecting a coating thickness in a thin film forming process, wherein the slice is extracted and a pure coating surface is extracted by smoothing an inclined curve between both base lines. The method of claim 12, The thickness of the coating film to be coated on the workpiece is extracted from the comparison of the vertex of the base line and the pure coating surface and any cell region shown in 3D coating thickness detection method in the thin film forming process. In the thin film forming process, Irradiating light having a wavelength distribution of a wide line width to the surface of the workpiece to be coated with the coating film; Analyzing light sensitivity by collecting light reflected from the surface of the workpiece; Extracting the thickness of the coating film using the sensitivity analyzed light by applying a line tracking technique and a vector analysis technique; And coating control of the discharge amount of the coating liquid for forming the coating film according to the thickness of the extracted coating film. The method of claim 16, In the thin film forming process, the pure coating film is extracted from the surface of the workpiece by the line tracing method, and the pure coating film extracted by the vector analysis method is implemented in 3D coordinates to extract the thickness deviation of the coating film from the curvature on the 3D coordinates. Coating thickness detection method.